Internal Blowout Preventer Apparatus

ABSTRACT

An internal blowout preventer assembly having a central through-bore and flapper valve. The flapper valve permits fluid flow in a downward direction, but not the opposite (upward) direction. A retrievable tubular lockout sleeve can be conveyed via wireline, coiled tubing or other similar means and installed within the through-bore of the internal blowout preventer assembly. Once installed, the lockout sleeve prevents the flapper valve from closing, thereby permitting wireline or other concentric operations to be performed (as well as upward fluid flow) though the internal blowout preventer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to an internal blowout preventer.

2. Brief Description of the Prior Art

Drilling rigs used for the drilling of oil and gas wells typicallyinclude a supportive rig floor positioned over a well, a derrickextending vertically above said rig floor, and lifting means which canbe raised and lowered within said derrick. During drilling andcompletion operations, work is typically performed in a well using drillpipe or other tubular work string that is installed in a number ofsections of roughly equal length called “joints”. As such, a typicaldrill string comprises a plurality of sections or joints of pipe, eachof which has an internal, longitudinally extending bore. When a greaterlength of pipe is required, additional joints of pipe must be added tothe string at the surface. Conversely, when a shorter length of pipe isdesired, joints of pipe are removed from the string at the surface.

During drilling operations, a fluid known as drilling mud or drillingfluid is normally pumped down the longitudinally extending bore of thetubular drill pipe, and circulated up the annular space which is formedbetween the external surface of said drill pipe and the internal surfaceof the wellbore. Functions of such drilling mud include, withoutlimitation, the following: (1) cooling and lubricating downholeequipment during drilling operations; (2) transportation of pieces ofdrilled-up rock and other debris from the bottom of the hole to thesurface; and (3) providing hydrostatic pressure to control encounteredsubsurface pressures.

When a well is drilled to a desired depth, large diameter pipe istypically installed in said well and cemented in place. The casingprovides structural support for the wellbore, while the cement protectsand seals the wellbore and isolates downhole formations from each other.Cementing is typically performed by pumping cement slurry down thecentral bore of the casing, thereby displacing drilling fluids presentwithin said casing. The cement slurry flows to the bottom of thewellbore, out the distal (bottom) end of the casing, and into theannular space existing between the outside of the casing and the innersurface of the wellbore. After the cement hardens, it forms a fluid sealand permanently positions the casing in place.

In many cases, it is desirable to set cement plugs at one or moredepth(s) within a well bore. This process, commonly referred to as“spotting cement”, typically involves a pumping a predetermined volumeof cement slurry down an open-ended length of drill pipe or work string.The cement is displaced with a predetermined volume of drilling fluids,such that the cement exits the bottom or distal end of the drill pipe orwork string and forms a plug within the well bore.

Internal blow-out preventers (“IBOPs”) have been known in the art formany years. Such IBOPs generally function like check valves, in that theIBOP's permit fluid flow in one direction, but not in the opposingdirection. Although IBOPs can be used in many different applications,IBOPs are frequently used during drilling operations and, morespecifically, during spotting of downhole cement plugs or other heavyfluids within a well bore. During such operations, the IBOPs generallypermit cement slurry and/or other heavy fluids to be pumped down drillpipe or work string, but prevent fluid flow into said drill pipe or workstring in the opposing direction (whether due to feed in from a downhole formation, or the U-tube fluid effect).

For example, at least one IBOP is often placed within a tubular workstring at desired depth(s) during such cementing operations. Heavycement slurry and other fluids can be pumped down the internal bore ofthe work string through the IBOP(s) and out the bottom or distal end ofthe work string; however, because flow is not permitted in the oppositedirection, the IBOP's prevent the cement slurry (which is typicallyheavier than other drilling fluids being used) from flowing back intothe workstring.

Unfortunately, existing IBOPs suffer from some significant limitations.Notably, prior art IBOPs typically include restrictions through theircentral bore. As a result, it is generally not possible to conductwireline, coiled tubing or other similar operations through said IBOPs.Thus, it is desirable to have an IBOP that has little or no restrictionthrough its central bore, such that the IBOP will permit the passage oftools conveyed via wireline, coiled tubing or other means to beperformed through such IBOP.

SUMMARY OF THE INVENTION

The present invention comprises an internal blowout preventer (IBOP)having a body defining a longitudinal central bore extending throughsaid body. The IBOP of the present invention permits single-directionfluid flow (typically downward) through said central bore. However, ahinged flapper connected to the body of said IBOP prevents upward fluidflow (that is, in the opposite direction) through said central bore. Dueto the configuration of the valve assembly of IBOP, and thesubstantially unobstructed central bore when said flapper is in the openposition, it is possible to conduct wireline, coiled tubing or othersimilar operations through said IBOP assembly.

When use of wireline, coiled tubing or the like is desired, said flappercan be locked into the open position using a sliding-sleeve, lock-outdevice or other similar apparatus. In this manner, said flapper will notimpede operations being conducted through the central bore of said IBOP,especially when such wireline and any connected tools are pulled upwardthrough said bore.

In an alternative embodiment of the present invention, said flapper cancomprise at least two opposing members that cooperate to block orrestrict fluid flow through said central bore. Further, the body of saidIBOP may also include an optional recess for receiving said flapper whenin the open position, thereby reducing protrusion of said flapper intosaid central bore.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe preferred embodiments, is better understood when read in conjunctionwith the appended drawings. For the purpose of illustrating theinvention, the drawings show certain preferred embodiments. It isunderstood, however, that the invention is not limited to the specificmethods and devices disclosed. Further, dimensions, materials and partnames are provided for illustration purposes only and not limitation.

FIG. 1 depicts a partially exploded side sectional view of the IBOPassembly of the present invention.

FIG. 2 depicts a partially exploded side sectional view of the IBOPassembly of the present invention rotated 180 degrees from the depictionin FIG. 1.

FIG. 3 depicts a side view of the IBOP assembly of the presentinvention.

FIG. 4 depicts a side sectional view of the IBOP assembly of the presentinvention along line 4-4 of FIG. 3.

FIG. 5 depicts a perspective view of an upper body member of the IBOP ofthe present invention.

FIG. 6 depicts a side view of an upper body member of the IBOP of thepresent invention.

FIG. 7 depicts a side sectional view of an upper body member IBOP of thepresent invention along line 7-7 of FIG. 6.

FIG. 8 depicts a side view of a lower body member of the IBOP assemblyof the present invention.

FIG. 9 depicts a side sectional view of a lower body member the IBOPassembly of the present invention along line 9-9 of FIG. 8.

FIG. 10 depicts a perspective view of a lockout sleeve of the IBOPassembly of the present invention.

FIG. 11 depicts a side view of a lockout sleeve of the IBOP assembly ofthe present invention.

FIG. 12 depicts a side sectional view of the IBOP assembly of thepresent invention along line 12-12 of FIG. 11.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 depicts a partially exploded side sectional view of IBOP 10 ofthe present invention. In the preferred embodiment, said IBOP 10 of thepresent invention comprises mating upper body member 30 and lower bodymember 20. Upper body member 30 has upper connection member 31; althoughother connection means can be used, in the preferred embodiment saidupper connection member 31 comprises a threaded female connector adaptedfor connection to a mating male threaded connector of drill pipe orother tubular work string. Through bore 32 extends through said upperbody member 30. Clevis bracket members 33 extend from end 34 of upperbody member 30.

Lower body member 20 has lower connection member 21; although otherconnection means can be used, in the preferred embodiment said lowerconnection member 21 comprises a threaded male connector adapted forconnection to a mating female threaded connector of drill pipe or othertubular work string. Through bore 22 extends through said lower bodymember 20.

IBOP assembly 10 further comprises a flapper assembly comprising flapper40 having clevis bracket members 43, flapper pivot pin 41 and biasspring 42. In the preferred embodiment, clevis bracket members 33 ofupper body member 30 are received between clevis bracket members 43 offlapper 40. Each of said clevis bracket members 33 and 43 have alignedbores for receiving flapper pivot pin 41. In this configuration, flappermember 40 can pivot or rotate about said pivot pin 41. Bias spring 42biases said flapper in a closed position (that is, closing through bore32) as described in detail below.

Still referring to FIG. 1 tubular lockout sleeve 50 has body member 51defining central through bore 52. In the preferred embodiment, the outerdiameter of body member 51 of tubular lockout sleeve 50 is smaller thanthe diameter of through bore 32 of upper body member 30, such that saidbody member 51 can be received within said through bore 32. Said tubularlockout sleeve further comprises upper collar member 53.

FIG. 2 depicts a partially exploded side sectional view of IBOP 10 ofthe present invention rotated 180 degrees from the depiction in FIG. 1.As noted in FIG. 1, IBOP 10 of the present invention comprises matingupper body member 30 and lower body member 20. Upper body member 30 hasupper connection member 31. Through bore 32 extends through said upperbody member 30. Similarly, lower body member 20 has lower connectionmember 21, and through bore 22 extends through said lower body member20.

Flapper member 40 is mounted using clevis bracket members 43 and pivotpin 41, and can pivot or rotate about the longitudinal axis of saidpivot pin 41. In the preferred embodiment, said flapper member 40 canrotate about an angle of approximately 90 degrees. In the open position,as depicted in FIG. 2, said flapper member 40 is disposed against therecessed inner wall of flapper housing 23 defined by lower body member20. In this position, said flapper 40 does not extend into or otherwiserestrict through bores 32 or 22.

Although not shown in FIG. 2, bias spring 42 biases said flapper member40 in a closed position during use of IBOP assembly 10. In such closedposition, said flapper member 40 is rotated approximately 90 degrees,such that a portion of said flapper 40 seats against end 34 of uppermember 30. In the preferred embodiment, when in the closed position,said flapper member 40 forms a fluid pressure seal against end 34, andprevents fluid from entering bore 32 of upper member 30 from below (thatis, from bore 22 of lower body member 20), If desired, end 34 and/orsealing surface 44 of flapper member 40 can be recessed or otherwiseshaped to engage with one another in order to facilitate a fluidpressure seal in a manner well known to those having skill in the art.

Tubular lockout sleeve 50 has body member 51 defining central throughbore 52. The outer diameter of body member 51 of tubular lockout sleeve50 is smaller than the diameter of through bore 32 of upper body member30, such that said body member 51 can be received within said throughbore 32. Said tubular lockout sleeve further comprises upper collarmember 53.

Still referring to FIG. 2, transverse bore 36 is disposed through upperbody member 30 and extends from the outer surface of said upper bodymember 30 to through bore 32. In the preferred embodiment, saidtransverse bore 36 is oriented substantially perpendicular to thelongitudinal axis of through bore 32. Retention pin 60 and spring 61 aredisposed within said transverse bore 36 and secured in place using cap62. Spring 61 biases said retention pin 60 inward in the direction ofbore 32 of upper body member 30.

Upper body member 30 has at least one recessed slot 35, while lower bodymember 20 has at least one recessed slot 25. When said upper body member30 is mated with lower body member 20, said recessed slots 25 and 35 arealigned. Locking clip 70 is received within said aligned slots 25 and35, and secured in place using locking clip pin 71.

FIG. 5 depicts a perspective view of upper body member 30 of IBOPassembly 10 of the present invention, while FIG. 6 depicts a side viewof said upper body member 30 of IBOP assembly 10 of the presentinvention. Said upper body member 30 comprises substantially cylindricalbody section 38, threads 37 and through bore 32. Clevis bracket members33, each having aligned bores 33 a, are disposed on end 34 of upper bodymember 30. Recessed slots 35 are formed in body section 38.

FIG. 7 depicts a side sectional view of upper body member 30 of IBOPassembly 10 of the present invention along line 7-7 of FIG. 6. Saidupper body member 30 comprises substantially cylindrical body section38, threads 37 and through bore 32. Clevis bracket members 37 aredisposed on end 34 of upper body member 30. Recessed slots 35 are formedin body section 38 of upper body member 30.

FIG. 8 depicts a side view of a lower body member 20 of IBOP assembly 10of the present invention, while FIG. 9 depicts a side sectional view ofsaid lower body member 20 of IBOP assembly 10 of the present inventionalong line 9-9 of FIG. 8. Said lower body member 20 comprisessubstantially cylindrical body section 28, internal threads 27 andthrough bore 22. Recessed slots 25 are formed in body section 28.

Threads 37 of upper body member 30 engage with threads 27 of lower bodymember 20 in order to threadedly connect said upper and lower bodymembers together. When said upper body member 30 is mated with lowerbody member 20, said recessed slots 25 and 35 are aligned. As describedabove, locking clip 70 is received within said aligned slots 25 and 35,and secured in place using locking clip pin 70 (which can be threaded orotherwise fasten locking clip 70 in place), to prevent said upper bodymember 30 and lower body member 20 from rotating (unscrewing) relativeto each other.

FIG. 10 depicts a perspective view of lockout sleeve 50 of IBOP assembly10 of the present invention. Tubular lockout sleeve 50 has body member51 defining central through bore 52, as well as upper collar member 53.Optional tapered surface 54 can be disposed at the opposite end oflockout sleeve 50 from said upper collar member 53. Circumferentialgroove 55 forms a slot or recess that extends around the circumferenceof said body member 51; in the preferred embodiment, saidcircumferential groove 55 is oriented substantially perpendicular to thelongitudinal axis of central bore 52.

FIG. 11 depicts a side view of lockout sleeve 50 of the presentinvention, while FIG. 12 depicts a side sectional view of lockout sleeve50 of the present invention along line 12-12 of FIG. 11. Body member 51defines central through bore 52. Upper collar member 53 is disposed atone end of said lockout sleeve 50, while optional tapered surface 54 isdisposed at the opposite end of lockout sleeve 50 from said upper collarmember 53. Circumferential groove 55 forms a slot or recess that extendsaround the circumference of said body member 51 and is orientedsubstantially perpendicular to the longitudinal axis of central bore 52.

Referring back to FIG. 3, a side view of IBOP assembly 10 of the presentinvention is depicted, In the preferred embodiment, said IBOP 10 of thepresent invention generally comprises mating upper body member 30 andlower body member 20. A locking clip 70 is received within alignedslots, and each clip 70 is secured in place using locking clip pin 71(which can be threaded or otherwise fasten locking clip 70 in place), toprevent said upper body member 30 and lower body member 20 from rotating(unscrewing) relative to each other.

FIG. 4 depicts a side sectional view of IBOP assembly 10 of the presentinvention along line 4-4 of FIG. 3. Through bore 32 extends through saidupper body member 30, while aligned through bore 22 extends through saidlower body member 20. Clevis bracket members 33 extend from end 34 ofupper body member 30.

IBOP assembly 10 further comprises a flapper assembly comprising flapper40 having clevis bracket members 43, flapper pivot pin 41 and biasspring 42 (not depicted in FIG. 4). In the preferred embodiment, clevisbracket members 33 of upper body member 30 are received between clevisbracket members 43 of flapper 40. Each of said clevis bracket members 33and 43 have aligned bores for receiving flapper pivot pin 41. In thisconfiguration, flapper member 40 can pivot or rotate about said pivotpin 41.

Still referring to FIG. 4, tubular lockout sleeve 50 has body member 51defining central through bore 52. Said tubular lockout sleeve 50 furthercomprises upper collar member 53 having a larger outside diameterdimension than that of body member 51. Optional tapered surface 54 canbe disposed at the opposite end of lockout sleeve 50 from said uppercollar member 53.

Flapper member 40 can rotate about an angle of approximately 90 degrees.In the open position, as depicted in FIG. 4, said flapper member 40 isdisposed against the recessed inner wall of flapper housing 23 definedby lower body member 20. In this position, said flapper 40 does notextend into or otherwise restrict through bores 32 or 22.

Still referring to FIG. 4, transverse bore 36 is disposed through upperbody member 30 and extends from the outer surface of said upper bodymember 30 to through bore 32. In the preferred embodiment, saidtransverse bore 36 is oriented substantially perpendicular to thelongitudinal axis of through bore 32. Retention pin 60 and spring 61 aredisposed within said transverse bore 36 and secured in place using cap62. Spring 61 biases said retention pin 60 inward in the direction ofbore 32 of upper body member 30.

In operation, IBOP assembly 10 of the present invention downward fluidflow through aligned through bores 32 and 22. Pivoting flapper 40,biased in a closed position by bias spring 42, prevents upward fluidflow (that is, in the opposite direction) through said aligned throughbores 32 and 22.

In certain circumstances, it may be beneficial to lock flapper 40 in theopen position. In such cases, lockout sleeve 50 can be run into the wellon wireline or other conveying means. Because the outer diameter of bodymember 51 of tubular lockout sleeve 50 is smaller than the diameter ofthrough bore 32 of upper body member 30, said body member 51 can bereceived within said through bore 32. Through bore 32 can include aninner profile or shape for receiving said collar member 53. Collarmember 53 has a greater diameter than through bore 32 of upper bodymember 30, thereby limiting downward travel of said lockout sleeve 50.Further, retention pin 60 can be received within circumferential groove55 to secure or “lock” said lockout sleeve 50 in place within IBOPassembly 10 and prevent axial movement of said lockout sleeve 50.

Due to the length of lockout sleeve 50, when said lockout sleeve 50 isinstalled, flapper 40 is prevented from closing, thereby preventing suchflapper from impeding wireline operations being conducted through IBOPassembly 10. Such wireline and any connected tools can pass in anunobstructed manner through central bore 51 of lockout sleeve 50,thereby allowing operations to be performed at depths below said IBOPassembly 10. Further, such wireline and tools can be safely retrieved tothe surface through said central bore 51 of lockout sleeve 50 withoutinterference from flapper 40 or any other components of IBOP assembly10.

The above-described invention has a number of particular features thatshould preferably be employed in combination, although each is usefulseparately without departure from the scope of the invention. While thepreferred embodiment of the present invention is shown and describedherein, it will be understood that the invention may be embodiedotherwise than herein specifically illustrated or described, and thatcertain changes in form and arrangement of parts and the specific mannerof practicing the invention may be made within the underlying idea orprinciples of the invention.

1. An internal blow out preventer comprising: a) a body member having atop, a bottom, a longitudinal axis and a through-bore extending fromsaid top to said bottom along said longitudinal axis; b) a flapperpivotally connected to said body member, wherein said flapper permitsfluid flow in one axial direction through said through bore but not theopposite axial direction; and c) a tubular sleeve member adapted to bereceived within said through bore of said body member, wherein saidtubular sleeve prevents said flapper from closing when said tubularsleeve member is installed in said through bore of said body member. 2.The internal blowout preventer of claim 1, further comprising: a) a pinhaving a first end and second end, movably received within a transversebore extending through said body member, wherein said transverse bore isoriented substantially perpendicular to said longitudinal axis of saidbody member, and said first end of said pin extends into said throughbore; b) a spring biasing said pin toward said through bore; and c) arecess on the outer surface of said tubular sleeve for receiving saidfirst end of said pin.
 3. The internal blowout preventer of claim 2,wherein said recess on the outer surface of said tubular sleevecomprises a groove extending substantially around the circumference ofsaid tubular sleeve.
 4. A method of conducting wireline operations in awell having a drill string equipped with an internal blow out preventer,comprising: a) installing an internal blowout preventer in a drillstring, said internal blowout preventer comprising: i) a body memberhaving a top, a bottom, a longitudinal axis and a through-bore extendingfrom said top to said bottom along said longitudinal axis; ii) a flapperpivotally connected to said body member, wherein said flapper permitsfluid flow in one axial direction through said through bore but not theopposite axial direction; b) installing a tubular sleeve member withinsaid through bore of said body member of said internal blowoutpreventer, wherein said tubular sleeve prevents said flapper fromclosing; and c) conducting wireline operations through said tubularsleeve member.
 5. The method of claim 4, wherein said internal blowoutpreventer further comprises: a. a pin having a first end and second end,movably received within a transverse bore extending through said bodymember, wherein said transverse bore is oriented substantiallyperpendicular to said longitudinal axis of said body member, and saidfirst end of said pin extends into said through bore; b. a springbiasing said pin toward said through bore; and c. a recess on the outersurface of said tubular sleeve for receiving said first end of said pin.6. The method of claim 5, wherein said recess on the outer surface ofsaid tubular sleeve comprises a groove extending substantially aroundthe circumference of said tubular sleeve.